Ventilation grid



FIG. 1 is a perspective view of a ventilation grid showing our new andornamental design;

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a rear view of FIG. 1; and,

FIG. 4 is a side view of FIG. 1.

CLAIM The ornamental design for a ventilation grid, as shown.